#include "PerlinNoise.h"

const int PerlinNoise::permutation[] = { 151, 160, 137, 91, 90, 15,
131, 13, 201, 95, 96, 53, 194, 233, 7, 225, 140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23,
190, 6, 148, 247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32, 57, 177, 33,
88, 237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175, 74, 165, 71, 134, 139, 48, 27, 166,
77, 146, 158, 231, 83, 111, 229, 122, 60, 211, 133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244,
102, 143, 54, 65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169, 200, 196,
135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64, 52, 217, 226, 250, 124, 123,
5, 202, 38, 147, 118, 126, 255, 82, 85, 212, 207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42,
223, 183, 170, 213, 119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9,
129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185, 112, 104, 218, 246, 97, 228,
251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241, 81, 51, 145, 235, 249, 14, 239, 107,
49, 192, 214, 31, 181, 199, 106, 157, 184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254,
138, 236, 205, 93, 222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180
};

float PerlinNoise::fade(float t){
	return t * t * t * (t * (t * 6 - 15) + 10);
}

float PerlinNoise::grad(int hash, float x, float y, float z){
	int h = hash & 15;                              // CONVERT LO 4 BITS OF HASH CODE
	float u = h < 8 ? x : y;                         // INTO 12 GRADIENT DIRECTIONS.
	float v = h < 4 ? y : h == 12 || h == 14 ? x : z;
	return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v);
}

float PerlinNoise::noise(float x, float y, float z){
	if (PerlinNoise::start)
	{
		for (int i = 0; i < 256; i++) p[256 + i] = p[i] = permutation[i];
		PerlinNoise::start = false;
	}

	int X = (int)floor(x) & 255;							// FIND UNIT CUBE THAT
	int Y = (int)floor(y) & 255;							// CONTAINS POINT.
	int Z = (int)floor(z) & 255;
	x -= floor(x);                                     // FIND RELATIVE X,Y,Z
	y -= floor(y);                                     // OF POINT IN CUBE.
	z -= floor(z);
	float u = fade(x);                                      // COMPUTE FADE CURVES
	float v = fade(y);                                      // FOR EACH OF X,Y,Z.
	float w = fade(z);

	int A = p[X] + Y;
	int AA = p[A] + Z;
	int AB = p[A + 1] + Z;                                  // HASH COORDINATES OF
	int B = p[X + 1] + Y;
	int BA = p[B] + Z;
	int BB = p[B + 1] + Z;                                  // THE 8 CUBE CORNERS,

	Interpolaters into = Interpolaters();

	return into.Lerp(into.Lerp(into.Lerp(grad(p[AA], x, y, z),			// AND ADD
		grad(p[BA], x - 1, y, z), u),                                   // BLENDED
		into.Lerp(grad(p[AB], x, y - 1, z),                             // RESULTS
		grad(p[BB], x - 1, y - 1, z), u), v),                           // FROM  8
		into.Lerp(into.Lerp(grad(p[AA + 1], x, y, z - 1),				// CORNERS
		grad(p[BA + 1], x - 1, y, z - 1), u),                           // OF CUBE
		into.Lerp(grad(p[AB + 1], x, y - 1, z - 1), grad(p[BB + 1], x - 1, y - 1, z - 1), u), v), w);
}

float PerlinNoise::Get1D(float x){
	return noise(x, 0, 0);
}

float PerlinNoise::Get2D(float x, float y){
	return noise(x, y, 0);
}

PerlinNoise::PerlinNoise()
{
}


PerlinNoise::~PerlinNoise()
{
}
